Method and apparatus for effecting expansion of gas



June 27, 1950 A. G. BROWN 2,512,916

. METHOD AND APPARATUS FOR EFFECTING EXPANSION OF GAS Filed April 9, 1945 2 Sheets-Sheet l \50 g 1 \51\ {f L v ab o 3 7 :(7 a

INVENTORL firefi (1132 0146 June 27, 1950 A. G. BROWN 2,512,916

METHOD AND APPARATUS FOR EFFECTING EXPANSION OF GAS Filed April 9, 1945 2 Sheets-Sheet 2 INVENTOR f/Zfrc 6! G157 2, BY k Patented June 27, 1950 METHOD AND APPARATUS FOR EFFECTING EXPANSION OF GAS Alfred G. Brown, Los Angeles, Calif., assignor of one-half to L. T. Sepin, Los Angeles County,

Calif.

Application April 9, 1943, Serial No. 482,400

1 Claim.

My invention has to do with the treatment and control of expansible gases. In its more particular aspects, but without being so limited, my invention contemplates method and apparatus for so controlling and treating carbon dioxide (CO2) gas as to utilize all or at least a major part of its latent properties of expansion.

It is well known, of course, that CO2 is one of the most compressible of industrial gases, being capable of expanding to many hundred times its original stored volume. I find, however, that fullest benefit cannot be taken of the potential or latent expansive characteristics of this gas by those methods and means presently known in the art, which methods and means employ only a single expansion from the solid to the gaseous state.

By my invention, I aim to provide method and apparatus capable of deriving from expansible gases, and particularly CO2 gas, maximum efficiency as a refrigerant.

Still further advantages are to be derived from my invention and how those as well as the foregoing specifically named objects are attained will become clear to those skilled in this art from the following detailed description of presently preferred procedures and forms of apparatus in which the invention may be carried out. I wish it understood at the outset, however, that, in its broader aspects as defined by the appended claims, my invention is not to be confined to the details of apparatus and method now to be described except insofar as those details may be specifically recited in the claims, since the invention is susceptible of being practiced in other manners and by other specific forms of apparatus.

Generally speaking, I carry my invention into practice by sublimation of CO2 from the solid to a gaseous state and then so controlling and treating the gas as to subject it to a series of expansion steps. I carry out cycles of alternate expansion and cooling until practically all the latent energy is derived from the gas. I here use the term latent energy to describe those .properties of expansion which, while possessed by the gas, have not heretofore been developed to .a point of utilization for power, refrigerant or other purposes.

In the following description I shall describe my invention as adapted to one of the many uses to which it may be put, namely as a refrigerating unit, and for that purpose reference will: be-made to the accompanying drawings, in which:

Fig. 1 is a vertical section of a refrigerating unit embodying my invention;

Fig. 2 is a section on line 2-2 of Fig. 1;

Fig. 3 is a section on line 3-3 of Fig. 1;

Fig. 4 is a section on line 4-4 of Fig. 1;

Fig. 5 is a section similar to Fig. 4 but showing a variational form; and

Fig. 6 is a fragmentary section showing a variational form of wall structure.

In Figs. '1 to 6, inclusive, I show an adaptation of my invention as a refrigerating unit. In this application of the invention I so control the movement and treatment of the gases as to cause them successively to be exposed to heat exchange surfaces of different temperatures whereby to effect the multiple expansion to which, in its broader aspects, my invention is directed.

Here I show a unit which may be placed in any area to be refrigerated. Within an outer casing 45 I nest two inner casings 46, 41 in such spaced relationship as to provide gas passageways P1, P2 therebetween.

Within innermost casing 41, and with its sides and ends spaced from the sides, top and bottom of said casing to provide gas passageway P, I dispose a block of solidified CO2 (dry ice), here designated by the reference letter I. Block I is supported on a perforated table 50, through the perforations in which gas is free to circulate. Casing 41 is supported at its bottom in spaced relation to the bottom of casing 46 by perforated corner brackets 55 and the bottom wall of casing 45 is supported in spaced relation to bottom Wall 45a of oasing 45.

The top end All) of innermost casing 41 is open but the top ends of casings d6, 45 are capped by domed covers 55, 56, respectively, detachably mounted on said casings by screw clamps F to be described. Cover 55 has an inner baffle 58, and there are restricted outlet ports 60, 6|, 62, respectively, through baffle 58, cover 55 and cover 56 to permit escape of gas as will be described.

- Bottom wall 450. is provided with a plurality of openings 65, for a purpose to be described, and has corrugations 66 to increase the surface area.

Beneathbottom wall 45a and in communication with the openings 65, I provide a plurality of sub-units S, only one of which I shall describe since all are of thesam'e construction. While I show nine of these subEunits, this number may be varied in particular units. Each sub-unit S consists of an outer casing ll] whose top periphery fits in fluid tight engagement against the under surface of bottom wall 45a and whose bottom wall" 15 is-spaced, byspacers 14-, about a half inch above the floor of a drip pan [6. The space 1 of casing 46. way P1, the cover55 and bafile'58 will deflect the gas inwardly and some of it will be recirculated in both passageways P and P1. of recirculation take place to the required extent,

entering tubes H through openings 11. thus re-entering, some of the gas will be drawn l into the cooler gas moving downwardly through the tubes Hrand will thus be subjected to reci-r-i cul-ation, and some of it, will pass out through around the sides and under the outer casings I is open to air circulation. Concentrically in each casing 10 I provide a tube 1| whose top periphery fits snugly against the under surface of bottom wall 45a, around an opening 65, and whose bottom end is spaced from bottom wall 15 by corner brackets 18. Each tube H is of relatively smaller cross-section than casings 10 whereby to provide a gas passageway therebetween, and four holes 11, one through each side wall, are provided adjacent the top end of each tube 1 I. Pan 16 may be-supported, as by corner brackets 80, upon, for instance, a base 19, which may be the floor of an enclosure to be refrigerated.

In Fig. 5 I show a variational way in which the outer tube 100. of each sub-unit S may be con-v In other respects the unit is the same as before described.

In Fig. 6 I show a variational form which the various casing walls before described may take.

Here, instead .of being plane as the walls of casings 4'5, 46, 4'7 are shown, said walls may be'corrugated as shown at 81 to provide greater surface area.

I shall now describe'the operation of my refrigerating unit illustrated in Figs. 1 to 6,,inclusive.

As the solid CO2 is Sublimated, the resultant heavy gas passes downwardly through the perforated table 50 and, beginning its expansion, forms a somewhat spiral, slowly upwardly moving stream of gasalong passageway P, the gas formed along the sides of block I moving slowly downwardly along the sides of the block into this upwardly moving stream. The expansion of this upwardly moving stream is accelerated by contact with the inner surface of casing 41. Upon reaching the top'of passageway P, some of the gas, by contact with the cooler gas moving downwardly adjacent block I, will be relativelycooled and will again recirculate in the manner described and some of it will pass over the top edge of casing 41 and will thence move downwardly again through passageway P1 along the outer surface of casing 4! towards the space beneath wall 41a, and as it further expands by exposure to the relatively 1 warmer inner surface of the side wall of casing 415, will move upwardly in a'somewhat spiralling stream along the inner surface of the side wall Upon reaching the top of passage- After these cycles and some of it will pass on downwardly through openings 65 into the sub-units .S, entering the tubes H, thence passing downwardly thereof,

through'the opened lower ends and thence upwardly between the tubes ,1! and casings 10, re-

Upon

openings 65 .and will there be drawn into gas moving downwardly into. another or other sub-units or will pass upwardly through passageway P2 into I the gas moving upwardly in that passageway.

After going through a number of those cycles of alternate expansion and cooling, the gas will eventually pass out through opening 62 in the top of outer casing 45.

While I show only two casings 4'6, 41 nested within the outer casing 45, I wish it understood that this number may be increased and a plurality of, sets of nested casings may be utilized within a single outer casing 45 if desired, depending upon the desired capacity and economy of a given unit.

This gas circulation is continuous until the block I is exhausted and it will be observed that in each cycle the gas is alternately expanded and cooled due to being exposed to heat transfer media of relatively different temperatures. I thus obtain multiple expansion and contraction of the gas until the maximum emciency is derived therefrom, with the result that the total refrigerating properties derived from a given quantity of Dry Ice are far in excess of those properties heretofore obtained.

The clamps F for securing the covers to the various casings are each comprised of a screw 9!] which is threaded through lock nuts 91 and, after passing through a hole in the cover, is threaded into a hole provided in an angle bracket 92 welded or otherwise suitably secured to the inner surface of the side wall of the carrying casing, a suitable sealing gasket 93 being provided between each bracket and cover.

' ThiS application is a continuation in part of my applicationfier-ial Number 457,553, filed September 7, 1942, now abandoned.

I claim:

Refrigerating apparatus comprising a cabinet having side wahs providing heat transfer surfaces, a pair of nested casings within the cabinet, the side walls of the casings providing heat transfer surf acesand being spaced apart and from the side walls of the cabinet to prov-idle gas passageways therebetween, means supporting a supply of solidified CO2 with its side walls spaced from the sidewalls of the innermost casing, a partition in the cabinet beneath the casings, said partition providing a space -below the casings in communication with the outermost passageway, holes through the partition, and a plurality of subexpansion members each in communication with one of the holes and each consisting of a pair of tubes nestedwith their side walls spaced apart to provide ao-gas passageway therebetween, the innermost tube of eachsub-expansion member being in communication at its top end with one of said openings and being in communication at each of its end portions with the gas passageway therearound.

ALFRED .G. BROWN.

REFERENCES CITED The following references-are of record in the file of this patent:

UNITED STATES PATENTS Number 

